Seal arrangements for pressurized dispensing containers

ABSTRACT

A pressurized dispensing apparatus includes a container for product to be dispensed and a valve for controlling outflow of product from the container. The valve includes a valve body (12) located within the container. The container includes an open ended container body (16) and a closure (15) fixedly attached to the container body for closing the open end thereof. The closure has an annular sidewall extending around at least the upper end of the container body. A first seal (20) is located in sealing engagement between the container body and the closure, and a second seal (25) is located in sealing engagement between the valve body and the container.

The invention relates to pressurized dispensing containers with animproved seal arrangement.

BACKGROUND ART

Pressurized dispensing containers are used for dispensing a wide varietyof products from mobile to viscous liquid products, powdered productsand the like and typically employ a liquid propellant such as ahydrocarbon or fluocarbon having sufficiently high vapor pressure atnormal working temperatures to propel the product through the dispensingapparatus. These are commonly used for dispensing pharmaceuticals andmedicaments.

Generally such pressurized dispensing containers comprise a container, adispensing valve and a closure which is crimped to the container to holdthe valve in place. A seal, usually made of an elastomeric material, iscompressed between the container and the closure to prevent leakage. Theefficiency of the sealing arrangement is particularly important toprevent the leakage of propellants. It is important that leakage isminimized, despite the latest propellants being more environmentallyfriendly than predecessors, to prevent the loss of the containercontents, ensuring that there are sufficient contents available afterstorage to meet the claims of the packaging and also to ensure that theratio of propellant to product remains constant.

It has hitherto been a problem that the deformation of the seal duringthe crimping operation can lead to a reduction in the effectiveness ofthe seal. During the crimping operation, the seal may also be deformedin a manner which does not provide a true seal.

Also it has hitherto been a problem that the permeability of the sealmaterial with respect to the propellants has led to loss of propellantduring storage of the container and during the shelf-life of theproduct.

To overcome such problems it has been proposed to use two seals, both ofwhich are sandwiched between the container and the closure. An exampleof such proposal is described in International patent specificationWO94/25373 in which is disclosed a pressurized dispensing containercomprising valve means, a valve body, an open ended container body, aclosure, a first seal between the container body and the closure and asecond seal between the valve body and the container, said seals beingindependent such that the second seal seals off the container body fromthe first seal.

It is an object of the present invention to provide a further improvedsealing arrangement for pressurized dispensing containers.

SUMMARY OF THE INVENTION

According to the invention there is therefore provided pressurizeddispensing apparatus comprising a container for product to be dispensed,valve means for controlling outflow of product from the container, saidvalve including a valve body located within the container, saidcontainer comprising an open ended container body and a closure fixedlyattached to said container body for closing the open end thereof, saidclosure having an annular sidewall extending around at least an upperend of the container body, said apparatus further comprising a firstseal located in sealing engagement between the container body and theclosure and a second seal located in sealing engagement between thevalve body and the container, the first and second seals comprisingindependent seal members positioned such that the second seal seals offthe container body from the first seal, characterized in that the firstseal is also in sealing engagement with the valve body.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred embodiment of the present invention will now be described,by way of example only, with reference to the accompanying drawings inwhich FIGS. 1 and 2 illustrate a metering valve known in the prior artfor use in a pressurizing dispensing container incorporating alternativeseal arrangements according to the present invention.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

Referring to FIGS. 1 and 2 a metering valve comprises a valve member 10in the form of a valve stem which is axially slidable within an annularmetering chamber 11. The metering chamber 11 and a portion of the valvemember 10 are located within a valve body 12. An outer seal 13 and aninner seal 14 extend radially between the valve member 10 and thechamber 11. The outer seal 13 is sandwiched between an upper end of themetering chamber 11 and a closure or ferrule 15 which is crimped to acontainer body 16 covering an open end therefore, thus providing aclosed container holding the product to be dispensed. The closure 15 hasa central aperture 17 through which the valve member 10 extends.Depression of the valve member 10 causes the product to exit thecontainer 16 from the chamber 11 through a passageway in the valvemember 10. The form and operation of the metering valve may be selectedas required.

The first seal 20 of the seal arrangement of the present invention islocated between an external surface of the upper end of the containerbody 16 and an inner surface of an annular sidewall of the closure 15.In the embodiments of the invention shown in FIGS. 1 and 2, the firstseal 20 is provided by a gasket in sealing engagement with the rimforming the annular opening 21 of the container body 16. The first seal20 is further in sealing engagement with a flanged section 22 of thevalve body 12. In FIGS. 1 and 2 this flanged section also has an annulargroove 23 which receives an annular ring 24 projecting from the firstseal 20. This groove and ring arrangement 23, 24 is optional, and helpsto locate and hold the first seal 20 in position relative to the valvebody 12, especially during the fitting and crimping operations.

A second seal 25, shown in FIGS. 1 and 2 as an O-ring, is provided insealing engagement with an internal surface of the container body 16,preferably at a neck portion thereof, and the valve body 12. The secondseal 25 may be retained by retention nodules 26 as illustrated in FIG. 1or within an annular groove 27 in the valve body 12 as illustrated inFIG. 2.

The second seal 25 thus seals off the main body of the container body 16from the first seal 20. This relieves the pressure on the first seal 20.Thus if that seal is weakened during the crimping operation, theintegrity of the overall seal will be less effected. Furthermore, thesecond seal 25 limits the quantity of propellant or product which canreach the first seal 20. Thus if there is a problem in the efficiency ofthat seal, again a quantity of leakage can be reduced significantly. Asthe second seal 25 is not in contact with the closure 15, it isunaffected by the crimping operation. This provides extra security inthe event that the first seal 20 is damaged in the crimping operation.

The first and second seals can be made from any appropriated material,including elastomers, rubbers (including nitrile rubbers),thermoplastics and so on. If the dispensing container is used formedicinal or pharmaceutical formulations, than an appropriate sealmaterial must be selected which does not contaminate the product.

Preferably the second seal is made of an ethylene-propylene-diene rubber("EPDM"). Optimally the first seal is also an EPDM gasket seal.Dispensing apparatus according to the present invention with seals fromsuch materials, are of particular use when propellants such as HFC-134aor HFC-227 are involved and varying levels of ethanol.

What is claimed is:
 1. Pressurized dispensing apparatus comprising acontainer for product to be dispensed, valve means for controllingoutflow of product from the container, said valve including a valve body(12) located within the container, said container comprising an openended container body (16) and a closure (15) fixedly attached to saidcontainer body (16) for closing the open end thereof, said closure (15)having an annular sidewall extending around at least an upper end of thecontainer body (16), said apparatus further comprising a first seal (20)located in sealing engagement between the container body (16) and theclosure (15) and a second seal (25) located in sealing engagementbetween the valve body (12) and the container, the first and secondseals (20, 25) comprising independent seal members positioned such thatthe second seal (25) seals off the container body (16) from the firstseal (20), characterized in that the first seal (20) is also in sealingengagement with the valve body (12).
 2. Pressurized dispensing apparatusas claimed in claim 1 in which the second seal (25) is located insealing engagement between the valve body (12) and the container body(16).
 3. Pressurized dispensing apparatus as claimed in claim 2 in whichat least one of the seals (20, 25) is an O-ring.
 4. Pressurizeddispensing apparatus as claimed in claim 2 in which the second seal (25)is located in an annular groove (27) in an external surface of the valvebody (12).
 5. Pressurized dispensing apparatus as claimed in claim 1 inwhich at least one of the seals (20, 25) is an O-ring.
 6. Pressurizeddispensing apparatus as claimed in claim 1 in which the second seal (25)is located in an annular groove (27) in an external surface of the valvebody (12).
 7. Pressurized dispensing apparatus as claimed in claim 1 inwhich the second seal (25) is held in position on the valve body (16) bymeans of locating nodules (26).
 8. Pressurized dispensing apparatus asclaimed in claim 1 in which the valve body (16) has a radially extendedflange (22) extending between a main body portion and the sidewall ofthe closure (15).
 9. Pressurized dispensing apparatus as claimed inclaim 8 in which a transverse face of the flange (22) provides a seatfor engagement with at least one of the seals (20, 25).
 10. Pressurizeddispensing apparatus as claimed in claim 9 in which an annular groove(23) is provided in the transverse face of the flange (22) for receivinga corresponding projection (24) on at least one of the seals in contacttherewith.
 11. Pressurized dispensing apparatus as claimed in claim 8 inwhich the flange (22) provides a further seal between the valve body(16) and the closure (15).